蜈蚣草-AM真菌对核素U污染土壤的联合修复作用

发布时间：2018-08-30 17:07

【摘要】：铀(uranium,U)是重要的核燃料,然而随着U矿的大量开采U污染问题日益严重,尤其对土壤环境的污染。目前关于U污染土壤的修复方法多样,其中生物修复法既经济实用又无二次污染,是U污染土壤修复的一条绿色通道。据研究表明蜈蚣草(Pteris vittata L.)对U污染土壤具有一定的抗性,且易被丛枝菌根(Arbuscular mycorrhizal,AM)真菌侵染形成互惠共生体,AM对有害金属污染的土壤也具有一定的修复作用。因此,本文以蜈蚣草为研究材料进行盆栽土壤试验,分别接种幼套球囊霉(Glomus etunicatum,Ge)、地表球囊霉(Glomus versiforme,Gv)、根内球囊霉(Glomus intraradices,Gi)3种AM真菌,筛选出蜈蚣草根际优势菌种。然后模拟铀污染土壤中,接种优势AM真菌,并添加螯合剂(O)做对照,探索不同时期蜈蚣草菌根对U污染土壤的修复效果,为AM真菌修复U污染土壤提供理论依据。主要研究结果如下:1、Gv是蜈蚣草根系优势AM真菌。Gv处理组菌根侵染率和根际土壤菌丝密度最高分别为52.88%、11.3 m·g-1(干土),Gv处理组蜈蚣草总生物量最大分别是Ge、Gi、CK组的1.13、1.54、2.17倍,差异显著。2、接种Gv有效促进蜈蚣草植株生长。同一时期Gv、Gv+O组生物量(干重)均大于CK组,且2013年12月及2014年3月、6月Gv组生物量均大于Gv+O组,说明Gv是促进蜈蚣草生物量增长的主要因素。3、接种Gv能够促进蜈蚣草富集U,主要促进根部富集。Gv组和Gv+O蜈蚣草富集系数均大于未接种Gv组,且大于1,说明Gv有助于促进蜈蚣草富集U,同一时期Gv组蜈蚣草根的富集系数是地上部分3.52、4.32、8.30、18.55倍,CK+O为5.31、7.63、7.25、12.00倍,Gv+O组为12.76、5.67、9.00、55.60倍,远远高于CK组,说明接种Gv有助于蜈蚣草对U的富集,且Gv主要促进蜈蚣草根部富集U,同时也缓解U对蜈蚣草的毒害作用。4、接种Gv有助于促进土壤中不同形态U转的移,主要促进蜈蚣草对铁锰氧化态和硫化物态U的吸收。接种Gv组土壤中总U含量小于CK组;接种Gv后蜈蚣草对铁锰氧化态和硫化物态U的吸收效果最好。5、螯合剂有助于促进菌根分泌球囊霉素,有助于蜈蚣草根部固定U。未接种菌剂组未检测到球囊霉素,Gv+O组易提取球囊霉素(EEG)含量和总球囊霉素(TG)含量均高于Gv组。6、接种Gv促进蜈蚣草各个器官对矿质元素的吸收。接种Gv不同程度的提高了蜈蚣草不同器官中矿质元素的含量。接种Gv后,蜈蚣草不同组织中增加幅度最大的是根茎叶中的N元素含量,分别是CK处理组的4.50倍、3.62倍和3.43倍。7、蜈蚣草中矿质元素含量与蜈蚣草富集U含量显著相关。蜈蚣草中U含量与Cu、Fe、Zn呈显著正相关,与N、P、Ca、Mg呈正相关,与K呈负相关。说明蜈蚣草菌根共生体通过促进矿质元素的吸收,间接提高蜈蚣草对U的吸收。
[Abstract]:Uranium (uranium,U) is an important nuclear fuel. However, with the extensive exploitation of U ore, the problem of U pollution is becoming more and more serious, especially the pollution of soil environment. At present, the remediation methods of U-contaminated soil are various, among which bioremediation is not only economical and practical, but also no secondary pollution. It is a green channel for the remediation of U-contaminated soil. Studies show that (Pteris vittata L.) of Pteris vittata The soil was resistant to U contamination and could be easily infected by arbuscular mycorrhizal (Arbuscular mycorrhizal,AM) fungi to form a symbiotic mutuality. Therefore, three kinds of AM fungi, Glomus etunicatum,Ge, Glomus versiforme,Gv and Glomus intraradices,Gi, were inoculated in potted soil with Pteris vittata as the research material, and the dominant species of Rhizosphere of Centipede were screened out. Then the dominant AM fungi were inoculated in the uranium-contaminated soil and the chelating agent (O) was added as the control to explore the remediation effect of the mycorrhizal fungi of Pteris vittata on the U-contaminated soil in different periods and to provide the theoretical basis for AM fungi to repair the U-contaminated soil. The main results were as follows: the percentage of mycorrhizal infection and the highest mycelial density of rhizosphere soil in the treatment group of AM fungi 路Gv were 52.88mg ~ (-1) (dry soil) and the maximum biomass of Pteris vittata was 1.131.542.17 times of that of the Ge,Gi,CK group, respectively. The difference was significant. 2. Inoculation with Gv could promote plant growth of Pteris vittata. In the same period, the biomass (dry weight) of Gv,Gv O group was higher than that of CK group, and the biomass of Gv group was higher than that of Gv O group in December 2013 and March and June 2014. The results showed that Gv was the main factor to increase the biomass of Pteris vittata. Inoculation with Gv could promote the enrichment of UVA vittata, and the enrichment coefficients of Gv and Gv O Pteris vittata were higher than those of uninoculated Gv. In the same period, the enrichment coefficient of Centipede root in Gv group was 3.52 ~ 4.32 ~ 8.30 ~ 18.55 times, CK _ O = 5.31 ~ 7.63 ~ 7.65 ~ (7.25) ~ (7.25) ~ (12.00) ~ 12.00 times that of GvO, which was much higher than that of CK group, which indicated that inoculation of Gv was helpful to the enrichment of U in Pteris vittata. Gv mainly promoted the enrichment of U in the roots of Pteris vittata, but also alleviated the toxicity of U to Pteris vittata. Inoculation of Gv could promote the migration of different forms of U in soil and the absorption of Fe and mn oxidized and sulfid U by Pteris vittata. The content of total U in soil of Gv group was lower than that of CK group, the absorption effect of Fe and S U in Pteris vittata was the best after Gv inoculation, the chelating agent was helpful to promote mycorrhizal secretion of balloon mycomycin and to fix Urocera vittata root. The contents of (EEG) and (TG) in GvO group were higher than those in Gv group. Inoculation of Gv promoted the absorption of mineral elements in every organ of Pteris vittata. Inoculation with Gv increased the content of mineral elements in different organs of Pteris vittata. After inoculation with Gv, the content of N in different tissues of Pteris vittata was 4.50 times, 3.62 times and 3.43 times as much as that of CK, respectively. The content of mineral elements in Pteris vittata was significantly related to the enrichment of U in Pteris vittata. U content in Pteris vittata was positively correlated with Cu,Fe,Zn, positively correlated with mg, and negatively correlated with K. The results showed that the mycorrhizal symbionts of Pteris vittata indirectly increased the absorption of U by promoting the absorption of mineral elements.
【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X172

【相似文献】